Predicting crop growth under different cropping and fertilizing management practices

Simulation models are widely used to make predictions of crop growth and yield, and soil carbon and nutrient dynamics under various agricultural practices and soil-climatic conditions. An analytical model of soil carbon and nutrient dynamics, K-model, was expanded to include a plant sub-model (K-Model-P). This allows for the prediction of short- and long-term crop growth, and soil carbon and nitrogen dynamics. The simulations for a short-term experiment (2 growing seasons) with three nitrogen application rates showed that K-Model-P correctly predicted the growth processes of above-ground plant biomass and grain yields. Predicted and measured daily accumulative biomass were significantly correlated, and differences were statistically insignificant. The simulation results for long-term experiments (70 years) of two crop rotations with three soil amendments showed that predicted and measured annual straw and grain yields were significantly correlated, with the differences of less than 13%. Annual crop straw and grain yields can be estimated by the model without significant errors. The agreement between the predicted daily growth and annual yields and experimental data illustrated that the K-Model-P can be used to produce reliable predictions for daily and annual crop growth.